Human platelet lysate improves the growth and survival of cultured human pre-antral follicles.

RESEARCH QUESTION: How do platelet-rich plasma products like human platelet lysate (HPL) and umbilical cord plasma (UCP) affect the growth and survival of isolated human pre-antral follicles in vitro? DESIGN: Human pre-antral follicles (n = 724; mean diameter: 75 µm; range: 46-237 µm) were isolated from ovarian medulla donated by 14 patients undergoing unilateral oophorectomy for ovarian tissue cryopreservation. Follicles were encapsulated in 0.5% alginate and cultured for 8 days in media supplemented with 5% fetal bovine serum (FBS) (n = 171), 2.5% human serum albumin (HSA) (n = 159), 5% HPL (n = 223) or 5% UCP (n = 171). RESULTS: The survival probability was significantly higher in the group supplemented with HPL (80%) compared with the other three groups: FBS (54%, P < 0.001); HSA (63%, P = 0.004) and UCP (29%, P < 0.001). Surviving follicles in the UCP group had less defined follicular membranes and decompacted granulosa cell layers. The median growth of surviving follicles was significantly (P < 0.001) larger in the HPL group (73 µm) compared with any of the other three groups: HSA (43 µm); FBS (40 µm) UCP (54 µm). A descriptive analysis of follicular secretion of anti-Müllerian hormone and oestradiol did not reveal any difference between the groups. The detectability of follicular genes was high for AR (100%), AMHR2 (100%) and FSHR (76%), whereas few follicles expressed LHR (20%). CONCLUSION: Human platelet lysate significantly improved survival and growth of cultured human pre-antral follicles compared with FBS, HSA and UCP. The use of HPL is a valuable improvement to culture human pre-antral follicles but further studies will have to prove whether the superiority of HPL translates into better quality oocytes.

Anti-Müllerian hormone and live birth in unexplained recurrent pregnancy loss.

RESEARCH QUESTION: Is anti-Müllerian hormone (AMH) associated with live birth rate (LBR) in women with unexplained recurrent pregnancy loss (RPL)? DESIGN: Cohort study of women with unexplained RPL attending the RPL Unit, Copenhagen University Hospital, Denmark, between 2015 and 2021. AMH concentration was assessed upon referral, and LBR in the next pregnancy. RPL was defined as three or more consecutive pregnancy losses. Regression analyses were adjusted for age, number of previous losses, body mass index, smoking, treatment with assisted reproductive technology (ART) and RPL treatments. RESULTS: A total of 629 women were included; 507 (80.6%) became pregnant after referral. Pregnancy rates were similar for women with low and high AMH compared to women with medium AMH (81.9, 80.3 and 79.7%, respectively) (low AMH: adjusted odds ratio [aOR] 1.44, 95% confidence interval [CI] 0.84-2.47, P = 0.18; high AMH: aOR 0.98, 95% CI 0.59-1.64, P = 0.95). AMH concentrations were not associated with live birth. LBR was 59.5% in women with low AMH, 66.1% with medium AMH and 65.1% with high AMH (low AMH: aOR 0.68, 95% CI 0.41-1.11, P = 0.12, high AMH: aOR 0.96, 95% CI 0.59-1.56, P = 0.87). Live birth was lower in ART pregnancies (aOR 0.57, 95% CI 0.33-0.97, P = 0.04) and with higher numbers of previous losses (aOR 0.81, 95% CI 0.68-0.95, P = 0.01). CONCLUSION: In women with unexplained RPL, AMH was not associated with the chances of live birth in the next pregnancy. Screening for AMH in all women with RPL is not supported by current evidence. The chance of live birth among women with unexplained RPL achieving pregnancy by ART was low and needs to be confirmed and explored in future studies.

Cryopreservation of ovarian tissue as fertility preservation in young women with multiple sclerosis before stem cell transplantation.

BACKGROUND: Women of fertile age who receive autologous hematopoietic stem cell transplantation (AHSCT) due to multiple sclerosis (MS) are at risk of loss of ovarian function and infertility because of the conditioning regimen with alkylating agents. OBJECTIVE: To present our data on fertility preservation by ovarian tissue cryopreservation (OTC) in young women with MS before AHSCT. METHODS: Retrospective, observational cohort study RESULTS: Eight women had OTC. After AHSCT four had premature ovarian insufficiency (POI), and two of these had autotransplantation of their cryopreserved ovarian tissue. Both women regained ovarian function, and a spontaneous pregnancy was achieved resulting in the delivery of a healthy baby. CONCLUSION: OTC preserves fertility in young women with MS at risk of POI.

Reproductive and Endocrine Outcomes in a Cohort of Danish Women following Auto-Transplantation of Frozen/Thawed Ovarian Tissue from a Single Center.

Ovarian tissue cryopreservation (OTC) is a method of fertility preservation in girls and young women prior to gonadotoxic treatment. It is a safe and promising method to restore fertility. The initial recovery of endocrine function is high, but the longevity of the grafted tissue varies. In this single-center, combined retro- and prospective cohort study, we report the reproductive outcome and hormonal recovery following ovarian tissue transplantation (OTT) and evaluate possible predictors of the chance of pregnancy. The study includes 40 women from eastern Denmark undergoing 53 OTTs between 2003 and 2021. Permission to obtain retrospective data was given by the Danish Patient Safety Authorities and prospective data-collection by informed consent. Initial recovery of endocrine function was seen in 18/19 women with POI, and ongoing function of the grafted tissue in 7/14 two years from OTT. Live birth rate (LBR) was 41%, with 20 children to 39 women trying to conceive. Women who conceived had higher AFC at the time of OTC than women who did not (p ± 0.04). Repeated transplantations were not successful in terms of delivery. Half of all pregnancies were achieved by ART, but PRs were lower after ART than by spontaneous conception. LBRs after OTT are encouraging. Chance of pregnancy after OTT is correlated to ovarian reserve at OTC. Repeated transplantations were not successful in terms of unfulfilled pregnancy wish.

[Oocyt donation].

The number of treatments with donated oocytes has risen markedly in Denmark during the latest decade due to changes in legislation and because female age is increasingly advanced when fertility treatment is warranted. Today, oocyte donation is a standard procedure offering the otherwise untreatable a high chance of achieving a pregnancy. Live birth rates as high as 35% per treatment are being reported. It is, however, important to be aware of increased risks of hypertensive disorders and bleeding complications in these pregnancies. As pointed out in this review, continuous research in the field is therefore highly needed.

Immediate versus postponed single blastocyst transfer in modified natural cycle frozen embryo transfer (mNC-FET): a study protocol for a multicentre randomised controlled trial.

INTRODUCTION: Today, it is widespread practice to postpone frozen embryo transfer (FET) in a modified natural cycle (mNC) for at least one menstrual cycle after oocyte retrieval and failed fresh embryo transfer or freeze-all. The rationale behind this practice is the concern that suboptimal ovarian, endometrial or endocrinological conditions following ovarian stimulation may have a negative impact on endometrial receptivity and implantation. However, two recent systematic reviews and meta-analyses based on retrospective data did not support this practice. As unnecessary delay in time to transfer and pregnancy should be avoided, the aim of this study is to investigate if immediate single blastocyst transfer in mNC-FET is non-inferior to standard postponed single blastocyst transfer in mNC-FET in terms of live birth rate. METHODS AND ANALYSIS: Multicentre randomised controlled non-blinded trial including 464 normo-ovulatory women aged 18-40 years undergoing single blastocyst mNC-FET after a failed fresh or freeze-all cycle. Participants are randomised 1:1 to either FET in the first menstrual cycle following the stimulated cycle (immediate FET) or FET in the second or subsequent cycle following the stimulated cycle (postponed FET). The study is designed as a non-inferiority trial and primary analyses will be performed as intention to treat and per protocol. ETHICS AND DISSEMINATION: Ethical approval has been granted by the Scientific Ethical Committee of the Capital Region of Denmark (J-nr.: H-19086300). Data will be handled according to Danish law on personal data protection in accordance with the general data protection regulation. Participants will complete written consent forms regarding participation in the study and storage of blood samples in a biobank for future research. The study will be monitored by a Good Clinical Practice (GCP)-trained study nurse not otherwise involved in the study. The results of this study will be disseminated by publication in international peer-reviewed scientific journals. TRIAL REGISTRATION NUMBER: NCT04748874; Pre-results.

Pregnancy outcomes following oocyte donation.

The use of oocyte donation (OD) has increased continuously over the last three decades, and it is now an indispensable part of assisted reproductive technology (ART). With OD, it has become possible to overcome the biological barrier of ovarian follicle pool depletion and the general age-related decline in fertility. This review contains a thorough appraisal of the safety of OD with an analysis of short-term pregnancy outcomes. Salient up-to-date evidence was evaluated, which revealed that in comparison with both IVF with autologous oocytes, and naturally conceived pregnancies, there is: (i) an increased risk of hypertensive disorders of pregnancy and preeclampsia; (ii) an increased risk of low birth weight and preterm birth and (iii) an increased risks of obstetric emergencies, following OD treatment. As a precaution, it is therefore highly encouraged to perform only single embryo transfer (SET) and to prescribe prophylactic low-dose aspirin during OD pregnancies.

Ovarian reserve markers and endocrine profile during oral contraception: Is there a link between the degree of ovarian suppression and AMH?

The ovarian reserve markers anti-Müllerian hormone (AMH) and antral follicle count (AFC) are suppressed in varying degree during the use of combined oral contraceptives (COC). Further, long-term use of COC can mask a condition of premature ovarian insufficiency. A desirable clinical tool that could distinguish true low ovarian reserve markers from COC-induced low levels during use of COC is warranted. The aim of this multicenter study including 235 COC users was to assess whether low age-adjusted AMH levels during COC use were linked to concomitant low levels of LH, FSH, estradiol and androgens - as a potential future tool to differentiate between 'false', COC-induced low AMH levels vs. true low AMH. Study population and methods: In total, 235 COC users from the general population aged 19-40 years were included. AMH, AFC and a reproductive hormonal profile were measured during COC intake. Age-adjusted AMH levels (Z-scores) were calculated from a comparison group of 983 non-users of COC. Differences in hormonal profile were tested between women with low versus high age-adjusted AMH-quartiles based on non-parametric Wilcoxon rank sum tests. The outcomes of interest were levels of gonadotropins, estradiol and androgens according to the four the age-adjusted AMH quartiles to find out if women with low age-adjusted AMH levels had a stronger gonadotropin suppression compared with women with higher age-adjusted AMH levels. Mean age of COC users was 30.2 years (SD 3.8), median AMH 14 pmol/l (inter-quartile range (IQR) 8.7-23)), median AFC 16 (IQR 11-25). We found no significant differences across the age-adjusted AMH quartiles in either the levels of gonadotropins, estrogens or androgens, respectively. Thus, the degree of suppression of FSH, LH, androgens and estradiol are unlikely to be a useful tool to differentiate between false low and true low ovarian reserve markers during COC use. Presently, there seems to be no alternative to withdrawal of the COC and to re-test the ovarian reserve after 2-3 months. Trial registration Trial no. NCT02785809 (www.clinicaltrials.gov).

Ovarian reserve markers in women using various hormonal contraceptives.

Objectives: The aim of the study was to assess whether the ovarian reserve markers anti-Müllerian hormone (AMH) and antral follicle count (AFC) were lower among women using the progestin-only pill (POP) or levonorgestrel-releasing intrauterine system (LNG-IUS) and similar to the decrease observed in combined oral contraceptive (COC) pill users.Methods: This retrospective study comprised 565 hormonal contraceptive users (COC, POP, LNG-IUS or contraceptive vaginal ring) and 983 non-hormonal contraceptive users, who were seen in two Danish fertility assessment and counselling clinics between 2015 and 2019. Adjusted multiple regression analysis was used to examine the differences in AMH and AFC between hormonal and non-hormonal contraceptive users.Results: Compared with non-hormonal contraceptive users, AMH was 31.1% lower among COC users [95% confidence interval (CI) -39.6%, -25.9%; p < 0.001], 35.6% lower among POP users (95% CI -49.0%, -18.6%; p < 0.001) and 17.1% lower among LNG-IUS users (95% CI -31.4%, 0.002%; p = 0.052); no significant differences were seen among vaginal ring users. Compared with non-hormonal contraceptive users, AFC was 31.3% lower among COC users (95% CI -35.0%, -25.3%; p < 0.001) and 29.7% lower among POP users (-39.1%, -17.9%; p < 0.001); no significant differences were seen among LNG-IUS or vaginal ring users. Ovarian volume was more than 50% reduced among COC and vaginal ring users (p < 0.001) but was unchanged among POP and LNG-IUS users.Conclusion: Assessment of ovarian reserve markers among users of all types of hormonal contraception should be interpreted cautiously and the type of contraceptive method considered.

Ovarian reserve markers after discontinuing long-term use of combined oral contraceptives.

RESEARCH QUESTION: How early do the ovarian reserve markers anti-Müllerian hormone (AMH) and antral follicle count (AFC) normalize after discontinuation of the long-term use of combined oral contraceptives (COC). DESIGN: This was a prospective cohort study of 68 women with a history of long-term COC use. Serum AMH concentrations, ovarian volume and AFC were measured during COC use and serially in a 4-month period after discontinuing COC: 1 and 2 weeks after discontinuation, and on cycle day 2-5 during three consecutive menstrual cycles. Changes in AMH and AFC were investigated using linear mixed models of repeated measurements adjusted for relevant covariates. RESULTS: Mean age was 29.4 years and mean duration of COC use 8.0 years. Baseline median AMH concentrations during COC use of 13 pmol/l (interquartile range [IQR] 8.4-22 pmol/l) increased to a median of 22.5 pmol/l (IQR 11-37 mol/l) 3 months after discontinuation. The estimated average increase was 53% (95% confidence interval [CI] 1.40-1.68, P < 0.001). AFC increased from a median value of 17 (IQR 11-25) to 24 (IQR 17-34). The estimated average increase was 41% (95% CI 1.30-1.52, P < 0.001). Ovarian volume increased from 2.4 to 5.8 ml (P < 0.001). The ovarian reserve markers increased continuously from baseline measurements until 2 months after discontinuation. Thereafter a plateau was reached. CONCLUSION: After discontinuation of COC, AMH increased by 53% and AFC by 41%, with values returning to normal within 2 months. This study provides clinicians with the highly relevant knowledge that AMH and AFC can be measured 2 months after discontinuation of COC without having to account for their influence.

[Fertility counselling of younger women after cancer treatment].

Girls and younger women of fertile age are at risk of infertility and premature ovarian insufficiency, if they have received chemotherapy or radiotherapy. While many are offered fertility preservation before treatment, many are left with a need for follow-up after treatment, which is pointed out in this review. At the fertility clinic at Rigshospitalet, Denmark, a follow-up clinic has been introduced for previous cancer patients with focus on reproductive health, including assessment of ovarian function, planning of future pregnancies and initiation of hormone replacement therapy if needed.

Concerns on future fertility among users and past-users of combined oral contraceptives: a questionnaire survey.

Objective: The combined oral contraceptive pill is the most preferred contraceptive method worldwide. Despite high life-time prevalence of infertility of 16-26%, scarce data about concerns of future fertility among COC users are available. We aimed to study whether COC usage induces concerns about fertility. Methods: Online questionnaire-based survey included 1283 current COC users and 1006 past users. The questionnaire covered knowledge and concerns of various aspects of fertility with respect to COC usage. Results: Significantly, more current users (66%) than past users (52%) had considered whether or not COC usage could affect future fertility (OR = 1.6, 95% CI 1.3-1.9). Nearly 50% of both groups believed COC usage could impair conception rates after discontinuation. Furthermore, 28% current vs. 19% past users believed COC could diminish the ovarian reserve more permanently. Conversely, 14% current and 11% past users believed that lack of ovulation could 'spare' the eggs (OR = 0.9, 95% CI 0.7-1.3). Significantly fewer current users (22%) vs. past users (35%) had heard, primarily by female friends, that a short break of 1-2 months during long-term COC usage was healthy, (OR 0.72, 95%CI = 0.56-0.92). Conclusions: Health care professionals prescribing hormonal contraception should be aware of misapprehensions and concerns of fertility among users of COC.

An AMH-based FSH dosing algorithm for OHSS risk reduction in first cycle antagonist protocol for IVF/ICSI.

The study assessed the impact of an AMH algorithm for FSH dosing in 589 patients to maintain pregnancy rates while minimizing OHSS rates in 1st antagonist cycles for IVF. Patients with low AMH < 12 pmol/L (n = 203) had maximal stimulation with corifollitropin, patients with AMH 12-32 pmol/L (n = 256) had standard stimulation with 150 IU/day of rFSH and patients with AMH > 32 pmol/L (n = 130) had minimal stimulation with 112 IU/day of HP-hMG. The proportion of patients with targeted (5-14) number of oocytes at retrieval was: Low AMH 42%, intermediate AMH 76% and high AMH 67% (p < 0.001). Low responses (≤ 4 oocytes) was found in 55%, 16% and 26% (p < 0.001) in the low, intermediate and high AMH group, respectively. Excessive responses (≥15 oocytes) was found in 2.5%, 6.2% and 6.1% in the low, intermediate and high AMH groups, respectively. Despite the high proportion of low responses, the ongoing pregnancy rates in the high AMH group was 41% per started cycle. A total of 14 patients had OHSS preventive actions like agonist triggering (n = 12) and/or cryopreservation of all embryos (n = 4) and all avoided OHSS. Three (0.5%) patients were admitted to hospital with severe OHSS, and all occurred after hCG triggering and all cases were late OHSS in relation to pregnancy. All were in the high AMH group after aspiration of 10-15 follicles. The conclusion is that among high AMH patients, low dose HP-hMG will limit the mean number of oocytes, without compromising pregnancy rates. The OHSS risk will be low, but as long as transfer after hCG triggering is used OHSS will occur unless a cut-off for OHSS preventive actions as low as 10-15 follicles is used.

The effect of preoperative cognitive impairment and type of vascular surgery procedure on postoperative delirium with associated cost implications.

OBJECTIVE: Postoperative delirium (POD) has a high prevalence among vascular surgery patients, increasing morbidity, mortality, and length of stay. We prospectively studied preoperative risk factors for delirium that can be assessed by the surgical team to identify high-risk patients and assessed its impact on hospital costs. METHODS: There were 173 elective vascular surgery patients assessed preoperatively for cognitive function using the Montreal Cognitive Assessment (MoCA) and the Confusion Assessment Method for POD, which was verified by chart and clinical review. Demographic information, medications, and a history of substance abuse, psychiatric disorders, and previous delirium were prospectively recorded. An accompanying retrospective chart review of an additional 434 (elective and emergency) vascular surgery patients provided supplemental cost information related to sitter use and prolonged hospitalization secondary to three factors: delirium alone, dementia alone, and delirium and dementia. RESULTS: Prospective screening of 173 patients (73.4% male; age, 69.9 ± 10.97 years) identified that 119 (68.8%) had MoCA scores <24, indicating cognitive impairment, with 7.5% having severe impairment (dementia). Patients who underwent amputation had significantly (P < .000) lower MoCA scores (17 of 30) compared with open surgery and endovascular aneurysm repair patients (23.7 of 30). The incidence of delirium was 11.6% in the elective cohort. Regression analysis identified predictors of delirium to be type of surgical procedure, including lower limb amputation (odds ratio [OR], 16.67; 95% confidence interval [CI], 3.41-71.54; P < .000) and open aortic repair (OR, 5.33; 95% CI, 1.91-14.89; P < .000); cognitive variables (dementia: OR, 5.63; 95% CI, 2.08-15.01; P < .001); MoCA scores ≤15, indicating moderate to severe impairment (OR, 6.13; 95% CI, 1.56-24.02; P = .02); and previous delirium (OR, 2.98; 95% CI, 1.11-7.96; P = .03). Retrospective review (N = 434) identified differences in sitter needs for patients with both delirium and dementia (mean, 13.6 days), delirium alone (mean, 3.9 days), or dementia alone (mean, <1 day [17.7 hours]). Fifteen patients required >200 hours (8.3 days), accounting for 69.7% of sitter costs for the surgical unit; 43.7% of costs were accounted for by patients with pre-existing cognitive impairment. CONCLUSIONS: POD is predicted by type of vascular surgery procedure, impaired cognition (MoCA), and previous delirium. Costs and morbidity related to delirium are greatest for those with impaired cognitive burden. Preoperative MoCA screening can identify those at highest risk, allowing procedure modification and informed care.

Low dose HP-hMG in an antagonist protocol for IVF in ovulatory and anovulatory patients with high AMH.

Women with high-AMH levels have an increased risk of ovarian hyperstimulation syndrome (OHSS). Studies have suggested that highly purified menotropin (HP-hMG) Menopur® reduces the risk. We, therefore, studied use of low-dose (112.5 IU/day) HP-hMG in ovulatory and anovulatory patients with high AMH (>32 pmol/L). The primary endpoint was the distribution of patients with appropriate, excessive, and inadequate response (5-14, ≥15, and ≤4 oocytes). Another endpoint was frequency of OHSS. Totally 115 women were included and 78 (67.8%) had an appropriate, 8 (7.0%) an excessive, and 29 (25.2%) an inadequate response. The number of oocytes was independent on AMH levels and ovulatory status but declined significantly with increasing bodyweight (R2 = 0.07, p < .01). The ongoing pregnancy rate per started cycle was 47.0%. Three (2.6%) developed OHSS, two had cancelation of the cycle and seven patients had GnRH agonist triggering to prevent OHSS. Selective use of a low dose of HP-hMG in patients with high levels of AMH provides 5-14 oocytes in more than two-thirds of the patients and is safe with low risk of OHSS. The number of aspirated oocytes was independent of AMH levels and ovulatory status, but inversely related to body weight.

A Case with Severe Endometriosis, Ovarian Hyperstimulation Syndrome, and Isolated Unilateral Pleural Effusion after IVF.

We present a very rare case of right-sided isolated pleural effusion in a patient with severe endometriosis who, in relation to in vitro fertilization (IVF), developed ovarian hyperstimulation syndrome (OHSS). Earlier laparotomy showed grade IV endometriosis including endometriotic implants of the diaphragm. The patient had no known risk factors for OHSS and only a moderate number of oocytes aspirated. She received, however, repeated hCG injections for luteal support. The patient did not achieve pregnancy but was hospitalized due to pain in the right side of the chest and dyspnoea. A chest computed tomography (CT) showed a pleural effusion on the right side. Total of 1000 ml of pleural fluid was drained after a single thoracentesis. After three days, the symptoms and fluid production ceased. Ascites is a common finding in OHSS, but pleural effusions are rare. Further, isolated pleural effusions have not previously been described in a patient with endometriosis. We suggest that the repeated hCG injections induced effusions from the endometriotic lesions at the diaphragm and as a consequence this patient developed isolated hydrothorax.

[Recurrent pregnancy loss].

Recurrent pregnancy loss (RPL) is defined as three or more consecutive pregnancy losses, and it affects 2-3% of couples trying to conceive. RPL is a multifactorial disorder, and only few evidence-based treatments are available. It is associated with an increased prevalence of stress and major depression, and also with immunogenetic markers, autoimmunity and an increase of the risk of cardiovascular disease in later life. Immunology seems to be a key element in RPL, and further research is needed to understand the pathogenesis of this heterogeneous condition in order to develop personalized treatment.

Applying 'drought' to potted plants by maintaining suboptimal soil moisture improves plant water relations.

Pot-based phenotyping of drought response sometimes maintains suboptimal soil water content by applying high-frequency deficit irrigation (HFDI). We examined the effect of this treatment on water and abscisic acid (ABA) relations of two species (Helianthus annuus and Populus nigra). Suboptimal soil water content was maintained by frequent irrigation, and compared with the effects of withholding water and with adequate irrigation. At the same average whole-pot soil moisture, frequent irrigation resulted in larger soil water content gradients, lower root and xylem ABA concentrations ([X-ABA]), along with higher transpiration rates or stomatal conductance, compared with plants from which water was withheld. [X-ABA] was not uniquely related to transpiration rate or stomatal conductance, as frequently irrigated plants showed partial stomatal closure compared with well-watered controls, without differing in [X-ABA] and, in H. annuus, [ABA]leaf. In two P. nigra genotypes differing in leaf area, the ratio between leaf area and root weight in the upper soil layer influenced the soil water content of this layer. Maintaining suboptimal soil water content alters water relations, which might become dependent on root distribution and leaf area, which influences soil water content gradients. Thus genotypic variation in 'drought tolerance' derived from phenotyping platforms must be carefully interpreted.

[Oocyte donation is associated with an increased risk of complications in the pregnant woman and the fetus].

In Denmark, oocyte donation is allowed for women below 46 years of age if sperm from the woman's husband/partner is used, thus assuring genetic relationship with one parent. New legislation has provided more donors implying both shorter waiting time until treatment and more pregnancies achieved with donated oocytes. Oocyte donation pregnancies have increased risks of pre-eclampsia, post-partum bleeding, caesarean section, low birth weight and preterm birth, and since these risks are aggravated in multiple pregnancies, single embryo transfer is recommended.